| Message ID | 20240629150313.GB4504@redhat.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | LoongArch: make the users of larch_insn_gen_break() constant | expand |
Hi, Oleg, On Sat, Jun 29, 2024 at 11:05 PM Oleg Nesterov <oleg@redhat.com> wrote: > > LoongArch defines UPROBE_SWBP_INSN as a function call and this breaks > arch_uprobe_trampoline() which uses it to initialize a static variable. > > Add the new "__builtin_constant_p" helper, __emit_break(), and redefine > the current users of larch_insn_gen_break() to use it. > > The patch adds check_emit_break() into kprobes.c and uprobes.c to test > this change. They can be removed if LoongArch boots at least once, but > otoh these 2 __init functions will be discarded by free_initmem(). > > Fixes: ff474a78cef5 ("uprobe: Add uretprobe syscall to speed up return probe") > Reported-by: Nathan Chancellor <nathan@kernel.org> > Closes: https://lore.kernel.org/all/20240614174822.GA1185149@thelio-3990X/ > Suggested-by: Andrii Nakryiko <andrii@kernel.org> > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > --- > arch/loongarch/include/asm/inst.h | 3 +++ > arch/loongarch/include/asm/uprobes.h | 4 ++-- > arch/loongarch/kernel/kprobes.c | 12 ++++++++++-- > arch/loongarch/kernel/uprobes.c | 8 ++++++++ > 4 files changed, 23 insertions(+), 4 deletions(-) > > diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h > index c3993fd88aba..944482063f14 100644 > --- a/arch/loongarch/include/asm/inst.h > +++ b/arch/loongarch/include/asm/inst.h > @@ -532,6 +532,9 @@ static inline void emit_##NAME(union loongarch_instruction *insn, \ > > DEF_EMIT_REG0I15_FORMAT(break, break_op) > > +/* like emit_break(imm) but returns a constant expression */ > +#define __emit_break(imm) ((u32)((imm) | (break_op << 15))) > + > #define DEF_EMIT_REG0I26_FORMAT(NAME, OP) \ > static inline void emit_##NAME(union loongarch_instruction *insn, \ > int offset) \ > diff --git a/arch/loongarch/include/asm/uprobes.h b/arch/loongarch/include/asm/uprobes.h > index c8f59983f702..99a0d198927f 100644 > --- a/arch/loongarch/include/asm/uprobes.h > +++ b/arch/loongarch/include/asm/uprobes.h > @@ -9,10 +9,10 @@ typedef u32 uprobe_opcode_t; > #define MAX_UINSN_BYTES 8 > #define UPROBE_XOL_SLOT_BYTES MAX_UINSN_BYTES > > -#define UPROBE_SWBP_INSN larch_insn_gen_break(BRK_UPROBE_BP) > +#define UPROBE_SWBP_INSN __emit_break(BRK_UPROBE_BP) > #define UPROBE_SWBP_INSN_SIZE LOONGARCH_INSN_SIZE > > -#define UPROBE_XOLBP_INSN larch_insn_gen_break(BRK_UPROBE_XOLBP) > +#define UPROBE_XOLBP_INSN __emit_break(BRK_UPROBE_XOLBP) > > struct arch_uprobe { > unsigned long resume_era; > diff --git a/arch/loongarch/kernel/kprobes.c b/arch/loongarch/kernel/kprobes.c > index 17b040bd6067..78cfaac52748 100644 > --- a/arch/loongarch/kernel/kprobes.c > +++ b/arch/loongarch/kernel/kprobes.c > @@ -4,8 +4,16 @@ > #include <linux/preempt.h> > #include <asm/break.h> > > -#define KPROBE_BP_INSN larch_insn_gen_break(BRK_KPROBE_BP) > -#define KPROBE_SSTEPBP_INSN larch_insn_gen_break(BRK_KPROBE_SSTEPBP) > +#define KPROBE_BP_INSN __emit_break(BRK_KPROBE_BP) > +#define KPROBE_SSTEPBP_INSN __emit_break(BRK_KPROBE_SSTEPBP) > + > +static __init int check_emit_break(void) > +{ > + BUG_ON(KPROBE_BP_INSN != larch_insn_gen_break(BRK_KPROBE_BP)); > + BUG_ON(KPROBE_SSTEPBP_INSN != larch_insn_gen_break(BRK_KPROBE_SSTEPBP)); > + return 0; > +} > +arch_initcall(check_emit_break); > > DEFINE_PER_CPU(struct kprobe *, current_kprobe); > DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); > diff --git a/arch/loongarch/kernel/uprobes.c b/arch/loongarch/kernel/uprobes.c > index 87abc7137b73..90462d94c28f 100644 > --- a/arch/loongarch/kernel/uprobes.c > +++ b/arch/loongarch/kernel/uprobes.c > @@ -7,6 +7,14 @@ > > #define UPROBE_TRAP_NR UINT_MAX > > +static __init int check_emit_break(void) > +{ > + BUG_ON(UPROBE_SWBP_INSN != larch_insn_gen_break(BRK_UPROBE_BP)); > + BUG_ON(UPROBE_XOLBP_INSN != larch_insn_gen_break(BRK_UPROBE_XOLBP)); > + return 0; > +} > +arch_initcall(check_emit_break); Do you mind if I remove the runtime checking after Tiezhu tests the correctness? Huacai > + > int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, > struct mm_struct *mm, unsigned long addr) > { > -- > 2.25.1.362.g51ebf55 > >
On 06/30, Huacai Chen wrote: > > > +static __init int check_emit_break(void) > > +{ > > + BUG_ON(UPROBE_SWBP_INSN != larch_insn_gen_break(BRK_UPROBE_BP)); > > + BUG_ON(UPROBE_XOLBP_INSN != larch_insn_gen_break(BRK_UPROBE_XOLBP)); > > + return 0; > > +} > > +arch_initcall(check_emit_break); > Do you mind if I remove the runtime checking after Tiezhu tests the correctness? Sure, please remove, thanks. Oleg.
On 06/29/2024 11:03 PM, Oleg Nesterov wrote: > LoongArch defines UPROBE_SWBP_INSN as a function call and this breaks > arch_uprobe_trampoline() which uses it to initialize a static variable. > > Add the new "__builtin_constant_p" helper, __emit_break(), and redefine > the current users of larch_insn_gen_break() to use it. > > The patch adds check_emit_break() into kprobes.c and uprobes.c to test > this change. They can be removed if LoongArch boots at least once, but > otoh these 2 __init functions will be discarded by free_initmem(). > > Fixes: ff474a78cef5 ("uprobe: Add uretprobe syscall to speed up return probe") > Reported-by: Nathan Chancellor <nathan@kernel.org> > Closes: https://lore.kernel.org/all/20240614174822.GA1185149@thelio-3990X/ > Suggested-by: Andrii Nakryiko <andrii@kernel.org> > Signed-off-by: Oleg Nesterov <oleg@redhat.com> Tested on LoongArch machine with Loongson-3A5000 and Loongson-3A6000 CPU, based on 6.10-rc3, KPROBE_BP_INSN == larch_insn_gen_break(BRK_KPROBE_BP) KPROBE_SSTEPBP_INSN == larch_insn_gen_break(BRK_KPROBE_SSTEPBP) UPROBE_SWBP_INSN == larch_insn_gen_break(BRK_UPROBE_BP) UPROBE_XOLBP_INSN == larch_insn_gen_break(BRK_UPROBE_XOLBP) The two functions check_emit_break() can be removed in arch/loongarch/kernel/kprobes.c and arch/loongarch/kernel/uprobes.c Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn> Thanks, Tiezhu
On Mon, Jul 1, 2024 at 2:22 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote: > > On 06/29/2024 11:03 PM, Oleg Nesterov wrote: > > LoongArch defines UPROBE_SWBP_INSN as a function call and this breaks > > arch_uprobe_trampoline() which uses it to initialize a static variable. > > > > Add the new "__builtin_constant_p" helper, __emit_break(), and redefine > > the current users of larch_insn_gen_break() to use it. > > > > The patch adds check_emit_break() into kprobes.c and uprobes.c to test > > this change. They can be removed if LoongArch boots at least once, but > > otoh these 2 __init functions will be discarded by free_initmem(). > > > > Fixes: ff474a78cef5 ("uprobe: Add uretprobe syscall to speed up return probe") > > Reported-by: Nathan Chancellor <nathan@kernel.org> > > Closes: https://lore.kernel.org/all/20240614174822.GA1185149@thelio-3990X/ > > Suggested-by: Andrii Nakryiko <andrii@kernel.org> > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > > Tested on LoongArch machine with Loongson-3A5000 and Loongson-3A6000 > CPU, based on 6.10-rc3, > > KPROBE_BP_INSN == larch_insn_gen_break(BRK_KPROBE_BP) > KPROBE_SSTEPBP_INSN == larch_insn_gen_break(BRK_KPROBE_SSTEPBP) > UPROBE_SWBP_INSN == larch_insn_gen_break(BRK_UPROBE_BP) > UPROBE_XOLBP_INSN == larch_insn_gen_break(BRK_UPROBE_XOLBP) > > The two functions check_emit_break() can be removed in > arch/loongarch/kernel/kprobes.c and arch/loongarch/kernel/uprobes.c > > Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn> Queued, thanks. Huacai > > Thanks, > Tiezhu > >
diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h index c3993fd88aba..944482063f14 100644 --- a/arch/loongarch/include/asm/inst.h +++ b/arch/loongarch/include/asm/inst.h @@ -532,6 +532,9 @@ static inline void emit_##NAME(union loongarch_instruction *insn, \ DEF_EMIT_REG0I15_FORMAT(break, break_op) +/* like emit_break(imm) but returns a constant expression */ +#define __emit_break(imm) ((u32)((imm) | (break_op << 15))) + #define DEF_EMIT_REG0I26_FORMAT(NAME, OP) \ static inline void emit_##NAME(union loongarch_instruction *insn, \ int offset) \ diff --git a/arch/loongarch/include/asm/uprobes.h b/arch/loongarch/include/asm/uprobes.h index c8f59983f702..99a0d198927f 100644 --- a/arch/loongarch/include/asm/uprobes.h +++ b/arch/loongarch/include/asm/uprobes.h @@ -9,10 +9,10 @@ typedef u32 uprobe_opcode_t; #define MAX_UINSN_BYTES 8 #define UPROBE_XOL_SLOT_BYTES MAX_UINSN_BYTES -#define UPROBE_SWBP_INSN larch_insn_gen_break(BRK_UPROBE_BP) +#define UPROBE_SWBP_INSN __emit_break(BRK_UPROBE_BP) #define UPROBE_SWBP_INSN_SIZE LOONGARCH_INSN_SIZE -#define UPROBE_XOLBP_INSN larch_insn_gen_break(BRK_UPROBE_XOLBP) +#define UPROBE_XOLBP_INSN __emit_break(BRK_UPROBE_XOLBP) struct arch_uprobe { unsigned long resume_era; diff --git a/arch/loongarch/kernel/kprobes.c b/arch/loongarch/kernel/kprobes.c index 17b040bd6067..78cfaac52748 100644 --- a/arch/loongarch/kernel/kprobes.c +++ b/arch/loongarch/kernel/kprobes.c @@ -4,8 +4,16 @@ #include <linux/preempt.h> #include <asm/break.h> -#define KPROBE_BP_INSN larch_insn_gen_break(BRK_KPROBE_BP) -#define KPROBE_SSTEPBP_INSN larch_insn_gen_break(BRK_KPROBE_SSTEPBP) +#define KPROBE_BP_INSN __emit_break(BRK_KPROBE_BP) +#define KPROBE_SSTEPBP_INSN __emit_break(BRK_KPROBE_SSTEPBP) + +static __init int check_emit_break(void) +{ + BUG_ON(KPROBE_BP_INSN != larch_insn_gen_break(BRK_KPROBE_BP)); + BUG_ON(KPROBE_SSTEPBP_INSN != larch_insn_gen_break(BRK_KPROBE_SSTEPBP)); + return 0; +} +arch_initcall(check_emit_break); DEFINE_PER_CPU(struct kprobe *, current_kprobe); DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); diff --git a/arch/loongarch/kernel/uprobes.c b/arch/loongarch/kernel/uprobes.c index 87abc7137b73..90462d94c28f 100644 --- a/arch/loongarch/kernel/uprobes.c +++ b/arch/loongarch/kernel/uprobes.c @@ -7,6 +7,14 @@ #define UPROBE_TRAP_NR UINT_MAX +static __init int check_emit_break(void) +{ + BUG_ON(UPROBE_SWBP_INSN != larch_insn_gen_break(BRK_UPROBE_BP)); + BUG_ON(UPROBE_XOLBP_INSN != larch_insn_gen_break(BRK_UPROBE_XOLBP)); + return 0; +} +arch_initcall(check_emit_break); + int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long addr) {
LoongArch defines UPROBE_SWBP_INSN as a function call and this breaks arch_uprobe_trampoline() which uses it to initialize a static variable. Add the new "__builtin_constant_p" helper, __emit_break(), and redefine the current users of larch_insn_gen_break() to use it. The patch adds check_emit_break() into kprobes.c and uprobes.c to test this change. They can be removed if LoongArch boots at least once, but otoh these 2 __init functions will be discarded by free_initmem(). Fixes: ff474a78cef5 ("uprobe: Add uretprobe syscall to speed up return probe") Reported-by: Nathan Chancellor <nathan@kernel.org> Closes: https://lore.kernel.org/all/20240614174822.GA1185149@thelio-3990X/ Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> --- arch/loongarch/include/asm/inst.h | 3 +++ arch/loongarch/include/asm/uprobes.h | 4 ++-- arch/loongarch/kernel/kprobes.c | 12 ++++++++++-- arch/loongarch/kernel/uprobes.c | 8 ++++++++ 4 files changed, 23 insertions(+), 4 deletions(-)